// 实现call
function Fn(a, b) {
  this.a = a
  this.b = b
  console.log('hello')
}

obj = {
  name:'jerry'
}

//----------------
Function.prototype._call = function (obj, ...other) {
  if (!(obj && obj instanceof Object)) { 
    obj = global
  }
  obj.fn = this
 return obj.fn(...other)
}
Fn._call(null, 1, 2)
console.log(obj)
